Automotive relays for use in 12 volt electrical systems. Relays are used when you need to switch higher currents than a switch can handle, or when you want to isolate an electrical circuit. Our relays have either 5 terminals or 4 terminals. Relays with 5 terminals are called Changeover Relays, and are capable of switching between two seperate output circuits. Similar to a single pole ON-ON switch, these relays can 'change over' from one circuit to another, and can be used to either turn a circuit on, or turn a circuit off.